Isolation, Characterisation and Identification of Bacteria from Three Different Unpasteurized Fruit Juices Sold at a Local Market in Guyana

Abstract

Fruit juices are widely consumed for their nutritional value. However, fruit juices that are unpasteurised may be unsafe to drink because they are not subject to heat processing and much of their human handling results in contamination. The fruits used to make these juices have resident microflora, transient bacteria from handling and equipment, and bacteria from water used to wash fruits and in some cases make the juice. The objective of this research was to determine the bacteria present in unpasteurised passionfruit, cherry, and tamarind juices respectively. Through the use of a survey, and standard methods for isolation, identification and characterisation of bacteria, the results showed that temperature and pH did not significantly affect the diversity of bacteria. Cherry juice had the highest number of Colony Forming Units while passion fruit juice had the lowest. In total seven (7) species of bacteria were found including E.coli, S. aureus, Lactobacillus sp, Acetobacter sp, Bacillus subtilis, Bacillus cereus, and Micrococcus. The results for the Colony Forming Units were found to be above maximum acceptable levels for fruit juices. The results of this study demonstrate that unpasteurised juices may be a threat to public health and hazardous to humans if not processed in a sanitary manner.